Everyone loves to watch hummingbirds—these tiny, brightly colored birds hovering around flowers and fiercely defending the safety of their feeders. But to the scientists who study them, hummingbirds are more than just an entertaining spectacle. Their tiny size and fast metabolism force them to live a tough life, sometimes shutting down their bodies almost completely to conserve energy so they can survive the night—or fly thousands of miles, sometimes across the open ocean.
The Energy Game
Hummingbirds’ nectar-rich diet raises their blood-sugar levels so high it could put a person into a coma. And their rapid flight sometimes generates so much G-force that a fighter pilot could faint. The more researchers look, the more surprises they discover hidden in those tiny bodies, the smallest in the bird world.
“They’re the only birds in the world that can fly upside down and backwards,” says conservation ecologist Holly Earnest of the University of Wyoming. “They drink pure sugar and don’t die of diabetes.”
Unique adaptations
Ernest is one of the few researchers studying how hummingbirds cope with the demands of their extreme lifestyle. Here are some of the unique adaptations scientists have learned about hummingbirds:
Putting in work
For many years, most researchers believed hummingbirds spent only about 30 percent of their day doing energy-intensive tasks, like drinking nectar from flowers, while resting most of the time. But when physiology ecologist Anusha Shankar looked deeper, she found they often work a lot harder than that.
Shankar, now at the Tata Institute of Fundamental Research in Hyderabad, estimated the daily expenditure of broad-billed hummingbirds in southern Arizona. They measured the birds’ metabolic rates during different activities and estimated their total daily energy expenditure. They then tried to figure out how much time throughout the day the birds were feeding versus spending sitting.
Comfort in the cold
Hummingbirds have a trick for preserving their energy: When a bird is in danger of running out of energy, it can cool down at night, bringing its body temperature to nearly the same as the surrounding air—sometimes just a few degrees above. In the cold, the bird appears to be in a near-coma, unable to respond quickly to external stimuli, and breathing only occasionally. This strategy can save up to 95 percent of its hourly metabolic expenditure on cold nights.
Managing sugars
To maintain their high metabolic rate, hummingbirds drink up to 80 percent of their body weight in nectar each day. That’s the same as a 150-pound person drinking about 100 20-ounce Cokes a day—and the nectar is often sweeter than soda. Hummingbirds cope with this challenge by having leaky intestines so that sugars can enter their bloodstream quickly. This rapid transport and other adaptations allow them to tolerate high blood-sugar levels that are six times higher than those seen in humans.
Saving water
It’s not just sugar, but nectar-rich diets also pose a challenge. Hummingbirds’ kidneys are adapted to reclaim electrolytes before urinating. “They urinate almost distilled water,” says Carlos Martinez del Rio. At night, hummingbirds shut down their kidneys to avoid dehydration.
Flying at high altitudes
The metabolic demands for hummingbirds are tougher at sea level. But many species live at high altitudes, where there’s less oxygen in the thin air. To cope with these conditions, birds have evolved more hemoglobin-rich blood.
Conclusion
The lifestyle of hummingbirds is a marvel. Their unique adaptability and survival strategies give them a unique place in the world of birds. Research conducted to understand the big mysteries hidden in their tiny bodies not only contributes significantly to the field of ornithology but also teaches us the wonders of the natural world.
FAQs
Q1: What makes hummingbirds’ lifestyle extreme?
A1: Hummingbirds have an extreme lifestyle due to their high metabolism, all-sugar diet, and incredible flight abilities. They need to consume a lot of nectar to maintain their energy levels, and their flight can generate high G-forces.
Q2: How do hummingbirds manage to survive on a nearly all-sugar diet?
A2: Hummingbirds have unique adaptations that allow them to process high levels of sugar without developing diabetes. Their bodies can rapidly absorb sugar from nectar and convert it into energy.
Q3: Can hummingbirds fly upside down and backwards?
A3: Yes, hummingbirds are the only birds in the world that can fly upside down and backwards. This unique ability is part of what makes them such fascinating creatures
